This invention generally relates to drive systems for vehicles. More particularly, this invention relates to a parallel drive system having components mounted at the axle for selectively powering a drive axle of the vehicle.
Vehicles typically are powered by an internal combustion engine or one or more electric motors. Some so-called hybrid vehicles include a combination of an internal combustion engine and electric motor power. Such hybrid vehicles sometimes include parallel drive systems that provide propulsion modes from the electric motor, internal combustion engine or both.
Typically the mechanical coupling that allows selection between electrical or internal combustion power is mounted directly to the internal combustion engine, vehicle transmission or a so-called summation gearbox that combines the electric drive with the mechanical drive. Such arrangements allow for a controller or the vehicle operator to select between the electrical power and the internal combustion power for driving the vehicle.
A major drawback associated with such systems is that special modifications are required for the engine flywheel or the transmission to accommodate the additional coupling required. In embodiments including a summation gearbox, the vehicle chassis also typically must be modified to accommodate the additional components. The economical drawbacks of such arrangements renders them less than ideal. Further, such modifications typically are difficult to implement.
Those skilled in the art are constantly striving to make improvements and to render parallel drive system more economical and usable.
This invention provides a unique arrangement that allows a parallel drive system to be used without requiring modification of the engine flywheel, transmission or vehicle chassis.